The role of gibberellins in the control of carbohydrate
metabolism in seedlings of sugarcane: a possible relationship
between cell wall expansion and sucrose accumulation
Marcos Buckeridge
Departamento de Botânica
Instituto de Biociências – USP
[email protected]
FAPESP, Cane Improvement Workshop, Mar. 2009
Sugarcane responses to the climatic changes
(CO2, temperature and water)
Sugarcane cell wall
(structure, architecture and metabolism)
Sugarcane physiology
(hormonal regulation of carbohydrate metabolism)
30% less transpiration
60% higher WUE
Productivity
Ambient
Elevated
Fiber(% FW)
Ambient
Elevated
Sucrose (% FW)
60% more Biomass
Ambient
6.62 ± 0.13
2.18 ± 0.20
Elevated
7.13 ± 0.21
2.82 ± 0.14*
How to modify the wall to obtain energy and
other valuable products?
Microorganisms
Change synthesis
Hydrolytic enzymes
Action on the
bagasse wall
Change polymer
structure
Control of hydrolysis
Expand the wall and
increase sucrose
Activation of
endogenous
hydrolysis
Change wall
architecture
Increase accessibility
cane with
modified walls
SOFTER WALLS
Increase accessibility
Free fermentable sugars
Green chemistry
Fermentation
Controlled enzyme hydrolysis
Ethanol
Oligosccharides, phenolics
wild
wild.+ GA3
Dwarf mutant
Dwarf + GA3
Effect of GA3 on
development of the
intercalar meristem of
of rice
Giberelinas and cell division
Giberelinas and
the cell cycle
Meristematic cell
vacuole
Mature cell
2d
4d
6d
7d
(PP333) (2RS, 3RS)-1-(4-chlorophenyl)-4,4dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol,
inhibits specifically the three steps in the
oxidation of the gibberellin-precursor entkaurene to ent-kaurenoic acid
Material and Methods
Seedlings were obtained from seeds (SP 87425 x SP 88813) donated by
CTC – Sugarcane Tecnology Center (Piracicaba, SP)
Grown in MS culture medium in the presence of GA3
The plants were washed with distilled water, dehydrated with progressive
concentrations of ethanol and fixed in Karnovisk.
The slides were stained with toluidine blue and analysed by light microscopy
GA3 7 days
Control 7 days
Paclobutrazol
GA and seed germination
Effect of GA3 on sucrose content of sugarcane seedlings
Biomass incorporation in sugarcane plants over
time of the presence of gibberellic acid ( M)
Total Plant Weight (mg)
5
a
4
b
bc
3
c
d
d
2
d
d
e
Control
Ga33 M
1
e
0
1
2
3
4
5
treatment time (days)
6
7
control
Vacuoles in meristematic cells
of sugarcane seedlings 6 days
old
GA
Sugarcane cell wall and elongation
control
3uM
30 uM
60 uM
0,5 cm
Design: Wanderley dos Santos
GlcA
XYL
GLUCURONOARABINOXYLAN (GAX)
alpha-(1,6)
XYL
XYL
XYL
XYL
XYL
XYL
XYL
alpha-(1,3)
ARA
beta-(1,4)
beta-(1,3)
ARA
MIXED LINKAGE GLUCAN (MLG)
GLC
beta-(1,4)
GLC
GLC
GLC
GLC
GLC
GLC
GLC
GLC
Sugar composition of sugarcane leaves
70
69,88
60
50
40
30
20
12,58
10
14,52
0,24
0
0,21
2,32
fuc
rham
ara
gal
glc
xyl
Collaboration with EMBRAPA Bioenergy and INCT do Bioetanol
Maria Thereza Bazzo Martins, Amanda P. De Souza, Hugo Molinari & Marcos Buckeridge
Sugar composition of sugarcane seedlings
60
51,8
50
40
30
23,6
16,7
20
7,9
10
0
0
0
fucose
arabinose
galactose
glucose
xylose
mannose
CONTROL
GA 3
PACLOBUTRAZOL
Changes in cell wall
composition during
Growth of sugarcane
seedlings
A
ATACKS OF XTH AND EXPANSIN
RELINK OF XYG BY XTH AND INTUSSUCEPTION
Buckeridge et al. 2008. Parede Celular, Cap 9 in Kerbauy G.B. Fisiologia Vegetal. Guanabara Koogan
Microfibril 2
New Microfibril
Microfibril 1
Microfibril 2
Microfibril 1
expansin
B
From 1999 to 2001, the SUCEST genome program
produced 238,000 ESTs from various tissues of the
sugar cane plant.
Since then we found:
1) 469 cell wall related genes in different cane tissues
(Lima et al. 2001, GMB)
1) Determined the chemical composition and structure of the cell wall
polymers of different sugarcane tissues
CONCLUSIONS
1)
2)
3)
4)
5)
6)
7)
GA increases sucrose
GA induces changes in the wall (expansion?)
Seedling is a good model to study Carb Metabolism
Maybe a way to taget cell division
May be a way to targed cell wall biosynthesis
How can we connect this to other hormones?
Seedlings could be a good model for systems approach
http://bioethanolbrazil.wordpress.com
Andrea Brandão
Gilberto Kerbauy
Gregorio Ceccantini
THANK YOU
[email protected]
Many thanks to
CTC (Sabrina)
Marcos Sanches
For the seeds!
http://bioethanolbrazil.wordpress.com
50
Elevated CO2
62,82%
CO2 Ambient
40
A umol m-2 s-1
30
20
10
0
0
500
1000
-10
1500
2000
2500
3000
PAR
250
Elevated CO2
CO2 Ambient
200
43,52%
CO2 assimilation and
electron transport rate of
sugarcane under elevated
CO2
ETR
150
100
50
0
0
500
1000
1500
PAR
2000
2500
3000
CO2 accelarates light harvesting:
how?
What is the signaling mechanism?
We found that four genes related to
light harvesting increase expression
under elevated CO2 and this leads to
increase of biomass.
Can we artificially express these genes in
chloroplasts and obtain the biomass effect
without need of elevation of
CO2 concentration?
% of shoots in the seedlings of sugarcane
Days
Control
Cont + PCZ PCZ
3 M GA
GA
7 61,25±0,03 c
28,75±0,07 d
-54
83,33±0,17 b
+36
14 60,78±0,07 c
33,33±0,17 d
-45
87,84±0,17 b
+44
21 50,17±0,17 c
40±0,02 d
-20
82,22±0,44 b
+64
28 53,97±0,09 b
40±0,02 c
-26
83,93±0,6 a
+55